ABSTRACT
Modern geologists show a tendency to withhold many of the millions of years that have hitherto been required for geological time. In some cases of sedimentary deposition, stone forms itself quickly enough. In Green Lake, New York State, for instance, algae are building fringing reefs of limestone. They deposit thick incrustation upon the branches and trunks of trees that have fallen into the water.1 At the Kensington Natural History Museum one may see similar incrustations upon a human skull recovered from the Tiber. At Knaresborough, near Harrogate, there is a petrifying well. Its water contains a large amount of dissolved minerals that are deposited upon objects suspended where the water drips over them. In Auvergne springs2 of similar powers, moulds of gutta-percha or sulphur taken from reliefs and cameos receive a limestone cast.3 Travertine, the limestone with which Rome was built, is daily deposited as fur in kettles. The boiling of water precipitates, in the form of calcium carbonate or limestone, the bicarbonate of calcium that our water holds in solution. The North Bridge, Edinburgh, was finished in 1772. In 1882, stalactites, an inch and a half in diameter, depended from it.
